Stators of electric machines are routinely made of a stack of laminations provided with coil receiving slots defined by projecting teeth therebetween. These slots generally need to be insulated from the coils that are to be placed therein. Insulating paper material has been developed for this purpose.
Conventionally, rolls of such insulating paper are cut and folded to form individual slot liners that are manually or automatically inserted into the slots. These liners are often U shaped with arms that are sized to extend out of the slot and thus help guide the coil therein while preventing the contact between the coil and the stack of laminations. Once the coils are inserted, the excess material of the slot liners is removed or folded on top of the coil and a slot closing member, generally referred to as a “wedge”, is inserted in the slot.
Many drawbacks are associated with this method of forming and installing slot liners. Indeed, manipulating many slot liners is cumbersome. Furthermore, the removal or folding of the excess material is an additional step that increases the manufacturing costs. Thirdly, since the teeth of the laminations are not fully covered by the slot liner, accidental contact between the laminations and the coil may occur and damage the electric machine.